Schaft



UNITED srA ns PATENT o IoE.-

BOTHO SCHWERIN, OF FRANKFORT-ON-THE-MAIN, GERMANY, ASSIGNOR TO GESELL- SCHAFT FUR ELEKTRO-OSMOSE M. B. H., OF FRANKFORT-ON-THE-MAIN, GERMANY,

A CORPORATION.

PROCESS FOR SEPARATION OF ADSORBED SUBSTANCES.

Specification of Letters Patent.

Patented Dec. 23, 1919.

llll'o Drawing. Application filed January 4, 1913, Serial No. 740,258. Renewed October 17, 1919. Serial No. 331,508.

'1 '0 all whom it may concern:

lie it known that I, Borne Souwrmm, a subject of the German Emperor, residing'a't Frankfort-on-the-Main, Germany, have invented certain new and useful Improvements in Processes for Separation of Adsorbed Substances, of which the following is a specification.

In German patent 205,628 I have shown that adsorbed bodies can be separated from adsorbents and vice versa by means of electro-osmosis. This process makes it possible to separate adsorbed, soluble, colloidal or finely subdivided substances from the substances which have adsorbed them and therefore either to free finely subdivided, soluble or colloidal substances from adsorptions that are not wanted, e. to clean the substances or to separate and acquire the adsorbed bodies.

It is particularly pointed out 1n the above named Letters Patent that by choice of a suitable porosity of the diaphragm through which the substances in question wander toward the pole there may be obtained a-fractionation of the material according to the size of the particles.

According to the present invention, there may be obtained, apart from the fractionation according to the size of the partlcles, a fractionation of the substances to be separated according to their degree of potential, by suitable selection of the material used for the diaphragms.

The nature of the diaphragm may vary in respect to its potential according to the material from which it is made. For example a diaphragm made of alumina (corundum) is electropositive, one of'silica may be regarded as negative, while one of earborundam is also electronegative but less strongly so than one of silica. Any desired degree of potential for the diaphragm, even a zero may be either soluble colloids or what may be called suspension colloids, separate correspondingly with the difference of potential of their charges from that of the diaphragm, in the sense that one will be held -p ass through it.

back by the diaphragm while another will The separation in this sense may be produced both at the anode and at. the cathode.

Obviously fractionation according to the potential difference may be combined with that according to the size of the particles, so that the present. invention affords the possibility of separating from a mixture, or from a solution a particular substance of a particular size of particle.

- The tungsten metal in ,its colloidal form has found a great employment in recent years, especially'for the manufacture of filaments for electric lamps. For this purpose it is necessary to use the metal in an absolutely pure form. With the means hitherto used, it is very diflic'ult to attain such a purity, because the impurities of the tech-' nical metal (71. 0. small quantities of tungsten acid, vanadium acid and alkalis) are present in the form of adsorptions and therefore they are adhering to the metal with particular obstinacy. \Vith my process however itis very easy to attain this separation by subjecting av colloidal solution of tungsten metal to electro-osmosis and using (liaphra'gms, whose electric potential is selected in consideration of the bodies which ought to be separated. I

Th process can be carried out in the following manner:

A diaphragm cell consisting of a mixture of carborundum and corundum, which is made according to the process described in my U. S. Patent 1,050,303, will be surrounded by a cathode made out of platinum wire gauze. Inside this cell there is a smaller diaphragm cell, which is formed from aluminum oxid and in the interior of this smaller cell the anode will be inserted which also may be formed from platinum wire gauze. The whole is put-in a vessel of non-conducting material, for instance num oxid cell (anode chamber) and the space between the carborundum corundum cell and the outer vessel. (cathodechamleer) is filledwith distilled water. If new a colloidal solution of technical tungsten metal is brought into the room between the two diaphragms, and the current is closed, the acid impurities will migrate through 'glass, and both the space inside the alumiterials from the media adsor the aluminum oxid diaphragm, which has a decidedly positive potential into the anode chamber. While the alkalic rests will mi-. grate into the Cathode chamber through the carborundum corundum diaphragm. This diaphragm has a slight pos tive character and therefore the colloidal tungsten will be hindered to migrate by this diaphragm may be called adsorptions, to electro-osmosis' between diaphragms, the electric potential of the diaphragms belng of such a degree, that the one component of the adsorption will be caused to migrate through the 'diaphragms, while the other components of the adsorption will be kept back between the diaphragms.

2. A process for separating adsorbed materials fromthe media adsorbing the same according to the difference in the electric potential and in the size of particle of the components by subjecting a suspension of these materials, which -may be called adsorptions, to electro-osmosis between diaphragms, the electric potential and the porosity of the diaphragms being of such a degree, that one component of the adsorption will be caused to migrate through the diaphragms, while the other'components'of the adsorption will be kept back between the diaphragms.

In testimony whereof I affix my signature in presence of two Witnesses.

BOTHO SCHWERIN.

Witnesses:

'- JEAN GRUND,

CARL GRUND. 

